#define  _CRT_SECURE_NO_WARNINGS  1
#include <stdio.h>
int main()
{
	int n;
	scanf("%d", &n);
	int t = 0;
	int a = n / 12;
	if (a >= 1)
	{
		t = 2 + a * 4;
	}
	else
	{
		t = 2;
	}

	printf("%d", t);

	return 0;
}